This research will continue a series of experiments on the discrimination of word-length auditory patterns. Certain major differences in human listeners' abilities to resolve the spectral, temporal, and intensive dimensions of the components of auditory patterns (tonal sequences), and their abilities to resolve the same components in isolation, have been demonstrated. The experiments are conducted using criterion-controlled psychophysical methods with which listeners are trained until approaching asympotic performance in various discrimination tasks. The primary new finding is that of a very strong tendency to distribute auditory attention systematically, but non-uniformly, over the spectral and temporal range of auditory patterns when the testing procedures force the listener to attempt to resolve the total information available within a pattern. A second, related, major finding is that the individual components of patterns can be resolved, essentially as accurately as when they are presented in isolation, when the testing procedure permits the listeners to focus on a specific component. The experiments on which these generalizations are based have now been extended to determine the spectral and temporal range of selective auditory attention, the course of auditory perceptual learning, the general role of stimulus uncertainty in auditory pattern perception, and the manner in which gross properties of auditory patterns serve as cues to selectively attend to specific pattern components. We plan additional experiments on each of these topics. The scope of these studies will next be increased to include the detetmination of individual differences in auditory pattern discrimination abilities among normal and impaired listeners, and to the refinement of a standardized test of these abilities. Auditory patterns consisting of sequences of sound synthesized to incorporate the resonant and source characteristics of the human vocal tract will also be investigated.